Grammar can be downright tricky. There are a ton of rules and guidelines to follow, and unless you consider yourself a grammarian, you probably don’t even know half of the rules and guidelines out there.

In your personal writing endeavors, you may not care too much about proper grammar, but in the workplace, using correct grammar makes you look more professional and helps your boss, clients and coworkers respect you.

There are common grammar mistakes that people make in their everyday writing, and there are common grammar mistakes that people tend to make in the workplace. In order to look more like a professional, make sure you’re not making any of these common workplace grammar mistakes.1. No Problem vs. You’re Welcome
If somebody, whether it’s your boss, a client or another coworker, thanks you for something, the proper response is “you’re welcome”. Saying “you’re welcome” is much more professional than saying “no problem”. The use of “no problem” tends to be used among younger professionals, but older professionals know that if you truly want to come across as a professional and sound sincere, you need to use “you’re welcome”.

2. Like
The word like should never be used as a filler in your business writing. You don’t write “uh” or “um” in your writing do you? (If so, there’s a bigger issue.) You should never use like as a filler in your business writing either. Your clients, boss or coworkers will like totally like not take you seriously if you do.

3. It’s vs. Its
The word it’s with an apostrophe simply stands for it is. That’s it. It’s confusing because most words have an apostrophe s to show possession, but not the word it. If you want to show the possession of it, you use its—sans apostrophe.

4. Then vs. Than
Then and than are not interchangeable. Then refers to timing, such as “it will take place then”. Than is typically used when comparing something, such as “I like the red coat more than the blue coat.”

5. Affect vs. Effect
Most people tend to have a problem with this, whether they’re writing for business or for personal reasons. Affect is typically used as a verb, and it means “to influence”. So you would say, “the rain affected my party”. Effect is typically used as a noun and means “a result”. So you would say, “the effects were gross.”

6. There vs. Their vs. They’re
These are commonly misused in the workplace and can make you seem completely incompetent if you don’t understand the difference. There refers to a place, such as “we are going there”. Their refers to possession, such as “their towels” or “their house”. They’re is a contraction for “they are”, so you would say “they’re going” or “they’re here”.

7. Disinterested vs. Uninterested
These two words are commonly intertwined, but they have two separate meanings. Disinterested means that you are impartial. Uninterested means that you are not at all interested in the topic.

You may not put a big emphasis on grammar, but it’s possible your clients, boss and coworkers do. Instead of making the common grammar mistakes in the workplace, use this information to learn right from wrong.

Kathryn Thompson is a business professional and avid writer. She highly stresses the importance of proper grammar for professionals in her writing.